Sludge settling and dewatering tank



17, 1948- c. B. SMITH ETAL SLUDGE SETTLING AND DEWATERING TANK 2 Sheets-Sheet 1 Filed March 25, 1946 INVENTOR.

Carlos cjhzifl BY Jr. ,BZ: 1100/2 Patented Aug. 17, 1948 OFFICE SIiUD'GE SETTLINGAND'DEWATERIN "TANK Carlos B. Smithand.HarrrLeslie BullOck; I a ,New York, N.. Y.

Application March"23, 194s,-sefla1Nonsense 5,

v, mins. (cram-:57)

:ilIhis VLin-Vention :lrela'te's :to improvements in sludge-settling; and'dewatering: tanks such as. used for the spurpose cd-f separating solids from a- 'circulating liquid .smedium -by the action of gravity in iturbid :flow. AH' ObJ EGt 'OI the inventiondsmo provideian apparatus which will i drain 'th'e liquid frcmrthe. collected :solids durin'g a period when theiflow ofzcirculatingiliquid isshu-t off' f-rom the tank, this rdrainingibein'g accomplished by using the collected ESO'lid'S :a's their lown filter medium. :An'other v:oh-iect :of the. invention is i to provide, inoaxstructure oI this character, an'arrangement of twlo isirnilar i or substantially similar :tanks, one of which Joe usedlfor :the continuous removal ofesol-idnnaterialafrom ithe icirculating fluid at the time 'ithatthei other tank "is" beingiused for the separation 'df"-lthe conveying lfiuid from the solidmiaterial contained within Lth'e latter tank, and-fforitheitemovaliof':the;;sludge. y :zStill sanotherxob'ject ofothe' inventicnzisvcto provide, tin-a 5StTJlCt11Eeof :this icharacter, aarseparatingrmeans arranged intheiformtof aconi'cal'zhelix disposedr verticallywin:the storm i'of a Ctnbular icolumnrand substantiallycentrallyof the-(tankiand byimeans :df which ;solid materia1 -.centering .the tankuwill be "(distributed iiinside lit) the: tank and ar oundrthexoutsiile :of th-e-zhelinwhile the liquid will udrain udown ithroughrithe :hellx 'Jandfito :the bottomzthereof fromwvlrrencexit mayfflowi through aisuitahle'coutlet'; s f I v'llheseand other '.objects :areiattained by rthe structure hereinafter described wand; rmore zpar-f ticu-larly :pointed '--.out :in' the 1::claims iapp'ended heretm I :1

:In athe accompanying drawings, wherein illustrative 'zembodhnentaofimhe :inven-tionzis wusclosed; 1 is an elevationalmiew of ard'ouble or -zduplexstankarrangement constructed :in accordance with -the invention one ot the -.tan-ks beingshown ,in section; Fig. #2 is aplan viewiof the structure ofTFigpl; .Eig. i3 is averticallsectional view of the upper portions ofQ-the helical column andithe parts Which'surround'itfFig. i4 is a sectional'view'of thelower end "of one of the tanks,' "showing =the"trap outlets through which the-"collected sludge i-s -ren1oved; "Fig, 5 is a sectlonal-View -6f -a part (if the -helix,f-showing th'e means for =ho-lding the convolutions in spaced relation; and -Fig. fi is a section'al view through a part of the lower end of one of the ta'nksfshowing the' drain 'outlet.

- This arrangement oiza i-su'pporting structure sis I the liquid into the system for re-deliverydnto.

t-an kican be u'sed, butf'sior'continuous or lunint'erruptedus'e, two tarikszare lpreferabletsincecone ot the* tanks can be usediforlreceiving thednflow at the -time' that the Jothertankiisilbeing cleaned 0f it's accumulatetlisludge. v

' iIf twoitanksiare lusedgfthey' are .DIBfGIEbIYBSUD- porteddn :si'de-by-side relationship. in the mannew-illustrated, :by assuitablessupporting.structure or :frame including :the :upright beams ;3 and "4, connected by various khorizontally "disposed supports, l some of which are shown :at :5, :26 and :I.

illustrative :since any zsuitalo'le arrangement for supporting the tanks :can he employed, the. essentialirequirement thereof :being that it 1 shall hold the ll'ower eendslxof"ithentanks elevated above. the

floor .to allowopening ofqthe trapor 'cl'ean-out doors with whichi-saidiends are provided,1and th-e emergence :df 1 the sludge therefrom intov suit-able collection'receptacles or trucks. N

:Both :of rthemtan'hs and their operating parts are similar in construction and 'th'ereforeragdee scription of vone-:of rthemwill isuffice for 'both.

Eachrltankis, in'-the form shown;-iof substantially cylindrical ;;shapeir-andofryhopper design, ':thus being :providedniwithn the conical lower end -8. Surrounding the upper endof the tank is a collectingl launder -9 having an inturnedflangeor bottoms ll 0 flocated--s1ightly below the upper I edge l=lrcif-the =bodyzof stheltank. The-bottom H! of the-launder-v9istprcvided with a discharge pipe l-3,-.discharging into an overflow and circulatingpumpsupply tank 112', said tank l2 being .supported ,upon the beams 14 of-the frame structure at a point .between-the-twotanks, and being provided'with an outletpipe :IzSathat -1SCO1}I16(-Zt6dt0 acirculating pump (notshown) which delivers thestank. w g

-At. the ton of the tank is EPI'OVidCd .a frame or spidenlfi having ca central annulus I1, in which is supported the-upper end of a helix l-8 wound in such a, -manner -tha;t .it :decreases in diameter from topic bottom. The helix is constructed from lrelativelynwid'efand flat striprmetal .andits conwolutions are .50} arranged that they overlap to some extenttut are maintained inslightly spaced relation, as indicated at l:3a*in-Figs;=3,-4 and-,5. .lIhevspaced-apartirelationsl'iipi of -theweon- Volu'tions .oithe zhelix :is desirable to .perrnit ithe passager oi:isclidsxto the'e'xterior of the helix andthe :drainage of :liquid "into -the interior 0f :the, helix,fas {will me -explained; i The helix, arranged asrdescfiibed,nand more clearly shownzin -Fig.1-1, is

column l8.

arranged centrally of the tank, and it has its lower or smaller end secured to the flange 2| rising from the inner face of the bottom 22 of the tank. Within the flange 2|, the bottom 22 of the tank is provided with a drain passage 23 (Fig. 5) leading from the bottom and connected as shown to a pipe 24 from whence the water is drained off.

Mounted over the upper end of the helix l8 and supported by the annulus I I is a distributing cone provided on its top with the velocity checks 26. Located above the cone 25 is an inlet pipe 21 provided at its end with the conical splash guard 28, held in place by the screw 29.

The water or other circulating fluid descends from the pipe 21 and flows over the distributing cone 25 to flow therefrom down into the tank, 1

and fill the same until the water level reaches the top edge ll of the tank and it then flows thereover into the launder 9 and out through the pipe I 3 and into the overflow supply tank I2. In passing from the edge .of the distributor cone 25 to the launder 9, the velocity of the water flow is reduced to a very low value and thus the solid material contained in the liquid sinks to the bottom of the tank around the outside of the helical As the solid material accumulates in-thetank, it builds up around the helical column 18 in the annular space 39 between the periphery of the helix and the wall of the tank. When the tank is two-thirds or three-fourths full of the solid material or sludge, the flow through inlet 21 is shut off and the drain connection 23, 24 is opened. Liquid present in the solid material will filter through such material and will pass through the spaces or apertures |3a between the convolutions of the helix 3 to thereby reach the inside of the helix and drain downwardly therein to reachthe outlet 23 where it is drained off through pipe 24.

The vertically-disposed helical column l8, being centrally positioned in the tank, forms the annular sludge-collection chamber 33 between it and the wall of the tank. Provided in the bottom 2-2- of the tank are sludge-discharge openings 3| and 32, normally closed by the pivoted trap doors 33'-and 34. Each of said doors is provided with the ears 6!), slotted as at 35 to loosely fit a pivot pin 36 mounted in lugs 31 formed on the bottom 22 of the tank. This pivotal arrangement of the trap doors allows the same to be swung upwardly and against the sealing gaskets 38 positioned around each of the outlet openings 31 and 32, to thereby seal said openings. It also permits the trap doors to be swung downwardly when it is desired to clean out the tank. The means for opening and closing the trap doors will be described.

The trap door indicated at 33 is provided with a centrally-positioned eye 39 arising from its inner face, and to which one end of a cable 40 is secured, said cable extending upwardly through the tank and extending around a, drum 4| secured on a cross-shaft 42. The shaft 42 is journalled at one end in a bearing 43 secured on a bar 44 extending across the top of the tank. The opposite end of the shaft 42 is journalled in bearing 45 mounted on the cross bar 46.

Secured on the shaft 42 is a worm gear 41 driven by a worm 48 on a tubular drive shaft 49, said shaft beingrotatively mounted in the bearings 5D and carrying a sprocket 5|, driven by a chain 52, extending from an electric motor, or a hand crank or other suitable source of power whereby the shaft 49 may be rotatedto cause a raised or lowered, or if desired, a simultaneous raising and lowering of the same may be made possible.

From the foregoing, the operation of the improvedtank construction will be readily understood. As previously explained, the tank is filled to the top by inflow from pipe 21, the water flow therefrom being directed by the conical distributor plate 25 into the annular sludge-collection and filtering chamber 30. solid material in the liquid will build up in the chamber 30 around the helical column l8, and liquid will filter through the solid material to drain through the aperture l3a between the convolutions of the helix, to drain down through the inside of the helix and out through the drain outlet 23. When the flow from drain outlet 23 ceases and the material in the tank has been dewatered to a maximum extent, the discharge or trap doors 33 and 34 are opened and the dewatered sludge then accumulated in the chamber. 30 is dropped into a truck or other container for removal. The trap doors 5;; 33 and 34 are then swung upwardly to closed position by winding of the cables 40 around the respective drums,,and the tank is then ready for another operating period. While the cleaningout operation above described is taking place in .1 connection with one of the tanks, the second tank can be in operation, and in this manner continuous operation is assured. However, in cases where a short interruption in operation is not inconvenient, a singletank n'eedonly be used.

The conical, centrally-disposed, helical column serves to provide. continuousdrainage from the top to the bottom of the tank, since the spirallyarranged aperture'between the spaced convolutions of the helix permits any solids in the liquid to drop down through this aperture to the bottom of the annular chamber 30 or to the top of the solid material already deposited therein. It is to be noted that the winding of the helix is so arranged that each convolution overlaps that situated below it, or in other words the upper convolution is .on the outside of the lower one in the overlapping area, similarly to the overlap of shingles on a roof, but with spacing between the overlapped partsas herein pointed out. Moreover, the winding of the helixin the manner described, resulting in the formation of a conical tubular column, produces an outside surface on the helix which forms an acute angle in respect to the vertical wall of the tank, with the apex of the angle toward thetop ofv the tank. Such a construction eliminates any surfaces likely to provide a wedging action which would lead to the bridging of solids between the walls of the tank and the helix.

Having described one embodiment of the invention, it is obvious that the same is not to be restricted thereto, but is broad enough to cover all structures coming within the scope of the annexed claims.

What we claim is:

1. In a structure of the character described, a tank having a vertically-disposed, centrally-arranged closed-top, tubular helix of fiat strip material extending from its top to its bottom and providing an annular sludge-collection chamber between it and the inner wall surface of the tank, an inlet located above the closed top of the helix the convolutions of the helix being in partly overlapped relation and being spaced apart to provide an aperture between them, the helix being of greatest diameter at its top and decreasing progressively in diameter from its top to its lower end, the tank having a bottom provided with means for receiving and supporting the lower end of its helix, said bottom being provided with a drain opening surrounded by the helix, and trap-doors at the bottom of the sludge-collection chamber for permitting removal of sludge therefrom.

2. In a structure of the character described,

a tank body having a spider at its upper end, a

bottom having a centrally-disposed annular wall surrounding a drain opening, a tubular conical helix of flat strip material having its upper end supported by the spider and. its lower end engaging the annular wall, the helix having the vertical wall surfaceslof its convolutions overlapped and spaced apart to provide an aperture between them.

3. In a, structure of the character described, a tank body of substantially cylindrical form, said tank having a normally closed bottom, a tubular column within the tank body, said column being in the form of a helix having its convolutions increasing in diameter from its lower end to its top partly overlapped and spaced to provide an aperture between them, the helix being of conical form with its end of lesser diameter located at the bottom of the tank, an annular launder located at the top of the tank, an overflow pipe leading therefrom, a distributing plate situated above and closing the upper end of the column, an inlet pipe located above and directing fluid against the distributing plate, the bottom of the tank body being provided with outlet openings, doors for normally closing said openings, means for operating said doors, and the bottom of the tank being provided with a drain opening surrounded by the lower end of the helix.

CARLOS B. SMITH.

HARRY LESLIE BULLOCK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 408,487 Jewell Aug. 6, 1889 765,182 King July 19, 1904 813,434 Jones Feb. 27, 1906 990,861 Hamill May 2, 1911 1,148,237 Kneuper July 27, 1915 1,757,187 Griffith May 6, 1930 1,787,634 Laubner Jan. 6, 1931 1,887,177 Adams Nov. 8, 1932 2,000,490 Mandahl May 7, 1935 2,064,511 Wells Dec. 15, 1936 2,077,074 Schneible Apr. 13, 1937 2,100,266 Perry Nov. 23, 1937 2,409,585 Piatt Oct. 15, 1946 FOREIGN PATENTS Number Country Date 461,162 Germany June 13, 1928 582,953 Germany Aug. 25, 1933 

